<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script>
			// var x=10;
			// console.log(x);//10
			
			// {//代码段
			// 	var x=100;
			// 	console.log(x);//100
			// }
			// console.log(x);//100
			
			let x =10;
			console.log(x);
			{
				let x=100;
				console.log(x);
			}
			console.log(x);
			//代码段中let定义变量作用域，代码段结束，里面的x也结束
			
			var sysname="学生管理系统";
			console.log(sysname);
			sysname = "mis";
			console.log(sysname);
			
			const PI =3.14;//常量
			console.log(PI);
			PI=3.1415926
			console.log(PI);
		</script>
	</head>
	<body>
		<h3>es6新标准案例</h3>
	</body>
</html>
